Kage no Jitsuryokusha ni Naritakute! (To Be a Power in the Shadows) [Licensed by Yen Press]

Just like how everyone adored heroes in their childhood, a certain young man adored those powers hidden in shadows. After hiding his strength and living the mediocre life of a mob character by day while undergoing frenzied training by night, he finally reincarnates into a different world and gains ultimate power. The young man who is only playing at being a power in the shadows, his misunderstanding subordinates, and a giant organization in the shadows that gets trampled….. This is the story of a young boy who had adored powers in shadows possibly eventually reigning over the world of shadows in another world.

This one seems like it would be an interesting series to pick up. Basic plot is guy wants to found a shadow organization, tells a girl who he saves this made up backstory on what his organization is out to do, he thinks its all fake. However, all of it ends up being real unbeknownst to the main character.

Would like to see this one picked up, looks like it only has 2 volumes as of now.
It's a funny story, the MC might look kind of dense but it's because he thinks all the things going on around him are just an act made by the girls he saved.
OP MC, reincarnated into another world, kinda harem-ish (as I said dense MC thinks all is an act), comedy, magic and swords.
I haven't seen other with a premise like this so I found it refreshing.